Commit Graph

1415 Commits

Author SHA1 Message Date
Heejin Ahn 5afdd64a53 [WebAssembly] Update InstPrinter and AsmParser for new EH instructions
This updates InstPrinter and AsmParser for `delegate` and `catch_all`
instructions. Both will reject programs with multiple `catch_all`s per a
single `try`. And InstPrinter uses `EHInstStack` to figure out whether
to print catch label comments: It does not print catch label comments
for second `catch` or `catch_all` in a `try`.

Reviewed By: aardappel

Differential Revision: https://reviews.llvm.org/D94051
2021-02-06 08:54:56 -08:00
Heejin Ahn be0efa1f23 [WebAssembly] Handle EH terminate pads for cleanup
Terminate pads, cleanup pads with `__clang_call_terminate` call, have
`catch` instruction in them because `__clang_call_terminate` takes an
exception pointer. But these terminate pads should be reached also in
case of foreign exception. So this pass attaches an additional
`catch_all` BB after every terminate pad BB, with a call to
`std::terminate`.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94050
2021-02-06 08:40:30 -08:00
Heejin Ahn 9f770b36cb [WebAssembly] Fix catch unwind mismatches
This fixes unwind destination mismatches caused by 'catch'es, which
occur when a foreign exception is not caught by the nearest `catch` and
the next outer `catch` is not the catch it should unwind to, or the next
unwind destination should be the caller instead. This kind of mismatches
didn't exist in the previous version of the spec, because in the
previous spec `catch` was effectively `catch_all`, catching all
exceptions.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94049
2021-02-06 07:13:38 -08:00
Heejin Ahn ed41945faa [WebAssembly] Fix call unwind mismatches
This adds `delegate` instruction and use it to fix unwind destination
mismatches created by marker placement in CFGStackify.

There are two kinds of unwind destination mismatches:
- Mismatches caused by throwing instructions (here we call it "call
  unwind mismatches", even though `throw` and `rethrow` can also cause
  mismatches)
- Mismatches caused by `catch`es, in case a foreign exception is not
  caught by the nearest `catch` and the next outer `catch` is not the
  catch it should unwind to. This kind of mismatches didn't exist in the
  previous version of the spec, because in the previous spec `catch` was
  effectively `catch_all`, catching all exceptions.

This implements routines to fix the first kind of unwind mismatches,
which we call "call unwind mismatches". The second mismatch (catch
unwind mismatches) will be fixed in a later CL.

This also reenables all previously disabled tests in cfg-stackify-eh.ll
and updates FileCheck lines to match the new spec. Two tests were
deleted because they specifically tested the way we fixed unwind
mismatches before using `exnref`s and branches, which we don't do
anymore.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94048
2021-02-06 07:07:04 -08:00
Wouter van Oortmerssen a872ee2f36 [WebAssembly] ensure .functype applies to right label in assembler
We used to require .functype immediately follows the label it sets the type of, but not all Clang output follows this rule.

Now we simply allow it on any symbol, but only assume its a function start for a defined symbol, which is simpler and more general.

Fixes (part of) https://bugs.llvm.org/show_bug.cgi?id=49036

Differential Revision: https://reviews.llvm.org/D96165
2021-02-05 15:36:15 -08:00
Wouter van Oortmerssen 5e5b2cb131 [WebAssembly] Prevent data inside text sections in assembly
This is not supported in Wasm, unless the data was encoded instructions, but that wouldn't work with the assembler's other functionality (enforcing nesting etc.).

Fixes: https://bugs.llvm.org/show_bug.cgi?id=48971

Differential Revision: https://reviews.llvm.org/D95838
2021-02-05 13:48:25 -08:00
Wouter van Oortmerssen e3c0b0fe09 [WebAssembly] locals can now be indirect in DWARF
This for example to indicate that byval args are represented by a pointer to a struct.
Followup to https://reviews.llvm.org/D94140

Differential Revision: https://reviews.llvm.org/D94347
2021-02-05 11:14:42 -08:00
Fangrui Song e5269da979 [ARM][WebAssembly] Fix incorrect MCOperand::createDFPImm after D96091 2021-02-04 20:39:52 -08:00
Craig Topper 11ef356d9e [TargetLowering] Use Align in allowsMisalignedMemoryAccesses.
Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D96097
2021-02-04 19:22:06 -08:00
Dan Gohman 698c6b0a09 [WebAssembly] Support single-floating-point immediate value
As mentioned in TODO comment, casting double to float causes NaNs to change bits.
To avoid the change, this patch adds support for single-floating-point immediate value on MachineCode.

Patch by Yuta Saito.

Differential Revision: https://reviews.llvm.org/D77384
2021-02-04 18:05:06 -08:00
Kazu Hirata 046cfb8565 [llvm] Forward-declare formatted_raw_ostream (NFC)
Various *TargetStreamer.h need formatted_raw_ostream but rely on a
forward declaration of formatted_raw_ostream in MCStreamer.h.  This
patch adds forward declarations right in *TargetStreamer.h.

While we are at it, this patch removes the one in MCStreamer.h, where
it is unnecessary.
2021-01-28 22:21:13 -08:00
Thomas Lively 4b68b64dcc [WebAssembly] Prototype i8x16 to i32x4 widening instructions
As proposed in https://github.com/WebAssembly/simd/pull/395 and matching the
opcodes used in V8:
https://chromium-review.googlesource.com/c/v8/v8/+/2617385/4/src/wasm/wasm-opcodes.h

Differential Revision: https://reviews.llvm.org/D95557
2021-01-28 10:59:32 -08:00
Wouter van Oortmerssen 275c6af7d7 [WebAssembly] Fix Fast ISEL not lowering 64-bit function pointers
Differential Revision: https://reviews.llvm.org/D95410
2021-01-28 10:05:29 -08:00
Kazu Hirata 8f5da41c4d [llvm] Construct SmallVector with iterator ranges (NFC) 2021-01-20 21:35:52 -08:00
Thomas Lively 11802eced5 [WebAssembly] Prototype new f64x2 conversions
As proposed in https://github.com/WebAssembly/simd/pull/383.

Differential Revision: https://reviews.llvm.org/D95012
2021-01-20 11:28:06 -08:00
Sam Clegg 96ef4f307d Revert "[WebAssembly] call_indirect issues table number relocs"
This reverts commit 418df4a6ab.

This change broke emscripten tests, I believe because it started
generating 5-byte a wide table index in the call_indirect instruction.
Neither v8 nor wabt seem to be able to handle that.  The spec
currently says that this is single 0x0 byte and:

"In future versions of WebAssembly, the zero byte occurring in the
encoding of the call_indirectcall_indirect instruction may be used to
index additional tables."

So we need to revisit this change.  For backwards compat I guess
we need to guarantee that __indirect_function_table is always at
address zero.   We could also consider making this a single-byte
relocation with and assert if have more than 127 tables (for now).

Differential Revision: https://reviews.llvm.org/D95005
2021-01-19 15:06:07 -08:00
Andy Wingo 418df4a6ab [WebAssembly] call_indirect issues table number relocs
This patch changes to make call_indirect explicitly refer to the
corresponding function table, residualizing TABLE_NUMBER relocs against
it.

With this change, wasm-ld now sees all references to tables, and can
link multiple tables.

Differential Revision: https://reviews.llvm.org/D90948
2021-01-19 09:32:45 +01:00
Kazu Hirata 23b0ab2acb [llvm] Use the default value of drop_begin (NFC) 2021-01-18 10:16:36 -08:00
Kazu Hirata 2082b10d10 [llvm] Use *::empty (NFC) 2021-01-16 09:40:55 -08:00
Kazu Hirata 2efcbe24a7 [llvm] Use llvm::drop_begin (NFC) 2021-01-14 20:30:33 -08:00
Heejin Ahn c93b955939 [WebAssembly] Remove more unnecessary brs in CFGStackify
After placing markers, we removed some unnecessary branches, but it only
handled the simplest case. This makes more unnecessary branches to be
removed.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94047
2021-01-12 01:18:10 -08:00
Heejin Ahn 1cc5235712 [WebAssembly] Misc. refactoring in CFGStackify (NFC)
Updating `ScopeTops` is something we frequently do in CFGStackify, so
this factors it out as a function. This also makes a few utility
functions templated so that they are not dependent on input vector
types and simplifies function parameters.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94046
2021-01-12 00:36:27 -08:00
Heejin Ahn 9f8b25769e [WebAssembly] Ensure terminate pads are a single BB
This ensures every single terminate pad is a single BB in the form of:
```
%exn = catch $__cpp_exception
call @__clang_call_terminate(%exn)
unreachable
```

This is a preparation for HandleEHTerminatePads pass, which will be
added in a later CL and will run after CFGStackify. That pass duplicates
terminate pads with a `catch_all` instruction, and duplicating it
becomes simpler if we can ensure every terminate pad is a single BB.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94045
2021-01-11 17:54:28 -08:00
Heejin Ahn 4e4df1e38d [WebAssembly] Remove unreachable EH pads
This removes unreachable EH pads in LateEHPrepare. This is not for
optimization but for preparation for CFGStackify. In CFGStackify, we
determine where to place `try` marker by computing the nearest common
dominator of all predecessors of an EH pad, but when an EH pad does not
have a predecessor, it becomes tricky. We can insert an empty dummy BB
before the EH pad and place the `try` there, but removing unreachable EH
pads is simpler.

This moves an existing exception label test from eh-label.mir to
exception.mir and adds a new test there.

This also adds some comments to existing methods.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94044
2021-01-09 03:42:38 -08:00
Heejin Ahn 0d8dfbb42a [WebAssembly] Update InstPrinter support for EH
- Updates InstPrinter to handle `catch_all`.
- Makes `rethrow` condition an early exit from the function to make the
  rest simpler.
- Unify label and catch counters. They don't need to be counted
  separately and this will help `delegate` instruction later.
- Removes `LastSeenEHInst` field. This was first introduced to handle
  when there are more than one `catch` blocks per `try`, but this was
  not implemented correctly and not being used at the moment anyway.
- Reenables all tests in cfg-stackify-eh.ll that don't deal with unwind
  destination mismatches, which will be handled in a later CL.

Reviewed By: dschuff, tlively, aardappel

Differential Revision: https://reviews.llvm.org/D94043
2021-01-09 02:42:35 -08:00
Heejin Ahn 52e240a072 [WebAssembly] Remove exnref and br_on_exn
This removes `exnref` type and `br_on_exn` instruction. This is
effectively NFC because most uses of these were already removed in the
previous CLs.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94041
2021-01-09 02:02:54 -08:00
Heejin Ahn 9e4eadeb13 [WebAssembly] Update basic EH instructions for the new spec
This implements basic instructions for the new spec.

- Adds new versions of instructions: `catch`, `catch_all`, and `rethrow`
- Adds support for instruction selection for the new instructions
 - `catch` needs a custom routine for the same reason `throw` needs one,
   to encode `__cpp_exception` tag symbol.
- Updates `WebAssembly::isCatch` utility function to include `catch_all`
  and Change code that compares an instruction's opcode with `catch` to
  use that function.
- LateEHPrepare
  - Previously in LateEHPrepare we added `catch` instruction to both
    `catchpad`s (for user catches) and `cleanuppad`s (for destructors).
    In the new version `catch` is generated from `llvm.catch` intrinsic
    in instruction selection phase, so we only need to add `catch_all`
    to the beginning of cleanup pads.
  - `catch` is generated from instruction selection, but we need to
    hoist the `catch` instruction to the beginning of every EH pad,
    because `catch` can be in the middle of the EH pad or even in a
    split BB from it after various code transformations.
  - Removes `addExceptionExtraction` function, which was used to
    generate `br_on_exn` before.
- CFGStackfiy: Deletes `fixUnwindMismatches` function. Running this
  function on the new instruction causes crashes, and the new version
  will be added in a later CL, whose contents will be completely
  different. So deleting the whole function will make the diff easier to
  read.
- Reenables all disabled tests in exception.ll and eh-lsda.ll and a
  single basic test in cfg-stackify-eh.ll.
- Updates existing tests to use the new assembly format. And deletes
  `br_on_exn` instructions from the tests and FileCheck lines.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94040
2021-01-09 01:48:06 -08:00
Heejin Ahn 9724c3cff4 [WebAssembly] Update WasmEHPrepare for the new spec
Clang generates `wasm.get.exception` and `wasm.get.ehselector`
intrinsics, which respectively return a caught exception value (a
pointer to some C++ exception struct) and a selector (an integer value
that tells which C++ `catch` clause the current exception matches, or
does not match any).

WasmEHPrepare is a pass that does some IR-level preparation before
instruction selection. Previously one of things we did in this pass was
to convert `wasm.get.exception` intrinsic calls to
`wasm.extract.exception` intrinsics. Their semantics were the same
except `wasm.extract.exception` did not have a token argument. We
maintained these two separate intrinsics with the same semantics because
instruction selection couldn't handle token arguments. This
`wasm.extract.exception` intrinsic was later converted to
`extract_exception` instruction in instruction selection, which was a
pseudo instruction to implement `br_on_exn`. Because `br_on_exn` pushed
an extracted value onto the value stack after the `end` instruction of a
`block`, but LLVM does not have a way of modeling that kind of behavior,
so this pseudo instruction was used to pull an extracted value out of
thin air, like this:
```
block $l0
  ...
  br_on_exn $cpp_exception $l0
  ...
end
extract_exception ;; pushes values onto the stack
```

In the new spec, we don't need this pseudo instruction anymore because
`catch` itself returns a value and we don't have `br_on_exn` anymore. In
the spec `catch` returns multiple values (like `br_on_exn`), but here we
assume it only returns a single i32, which is sufficient to support C++.

So this renames `wasm.get.exception` intrinsic to `wasm.catch`. Because
this CL does not yet contain instruction selection for `wasm.catch`
intrinsic, all `RUN` lines in exception.ll, eh-lsda.ll, and
cfg-stackify-eh.ll, and a single `RUN` line in wasm-eh.cpp (which is an
end-to-end test from C++ source to assembly) fail. So this CL
temporarily disables those `RUN` lines, and for those test files without
any valid remaining `RUN` lines, adds a dummy `RUN` line to make them
pass. These tests will be reenabled in later CLs.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94039
2021-01-08 23:38:26 -08:00
Heejin Ahn 7be271537e [WebAssembly] Rename wasm_rethrow_in_catch intrinsic/builtin
`wasm_rethrow_in_catch` intrinsic and builtin are used in order to
rethrow an exception when the exception is caught but there is no
matching clause within the current `catch`. For example,
```
try {
  foo();
} catch (int n) {
  ...
}
```
If the caught exception does not correspond to C++ `int` type, it should
be rethrown. These intrinsic/builtin were renamed `rethrow_in_catch`
because at the time I thought there would be another intrinsic for C++'s
`throw` keyword, which rethrows an exception. It turned out that `throw`
keyword doesn't require wasm's `rethrow` instruction, so we rename
`rethrow_in_catch` to just `rethrow` here.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94038
2021-01-08 06:55:04 -08:00
Kazu Hirata b934160aaa [Target] Use llvm::find_if (NFC) 2021-01-07 20:29:36 -08:00
Wouter van Oortmerssen 5c38ae36c5 [WebAssembly] Fixed byval args missing DWARF DW_AT_LOCATION
A struct in C passed by value did not get debug information. Such values are currently
lowered to a Wasm local even in -O0 (not to an alloca like on other archs), which becomes
a Target Index operand (TI_LOCAL). The DWARF writing code was not emitting locations
in for TI's specifically if the location is a single range (not a list).

In addition, the ExplicitLocals pass which removes the ARGUMENT pseudo instructions did
not update the associated DBG_VALUEs, and couldn't even find these values since the code
assumed such instructions are adjacent, which is not the case here.

Also fixed asm printing of TIs needed by a test.

Differential Revision: https://reviews.llvm.org/D94140
2021-01-07 10:31:38 -08:00
Matt Arsenault c9122ddef5 CodeGen: Refactor regallocator command line and target selection
Make the sequence of passes to select and rewrite instructions to
physical registers be a target callback. This is to prepare to allow
targets to split register allocation into multiple phases.
2021-01-07 13:13:25 -05:00
Thomas Lively 497026c902 [WebAssembly] Prototype prefetch instructions
As proposed in https://github.com/WebAssembly/simd/pull/352 and using the
opcodes used in the V8 prototype:
https://chromium-review.googlesource.com/c/v8/v8/+/2543167. These instructions
are only usable via intrinsics and clang builtins to make them opt-in while they
are being benchmarked.

Differential Revision: https://reviews.llvm.org/D93883
2021-01-05 11:32:03 -08:00
Andy Wingo 9ad83fd6dc [WebAssembly] call_indirect causes indirect function table import
For wasm-ld table linking work to proceed, object files should indicate
if they use an indirect function table.  In the future this will be done
by the usual symbols and relocations mechanism, but until that support
lands in the linker, the presence of an `__indirect_function_table` in
the object file's import section shows that the object file needs an
indirect function table.

Prior to https://reviews.llvm.org/D91637, this condition was met by all
object files residualizing an `__indirect_function_table` import.

Since https://reviews.llvm.org/D91637, the intention has been that only
those object files needing an indirect function table would have the
`__indirect_function_table` import.  However, we missed the case of
object files which use the table via `call_indirect` but which
themselves do not declare any indirect functions.

This changeset makes it so that when we lower a call to `call_indirect`,
that we ensure that a `__indirect_function_table` symbol is present and
that it will be propagated to the linker.

A followup patch will revise this mechanism to make an explicit link
between `call_indirect` and its associated indirect function table; see
https://reviews.llvm.org/D90948.

Differential Revision: https://reviews.llvm.org/D92840
2021-01-05 11:09:24 +01:00
Heejin Ahn c4f12a07a4 [WebAssembly] Remove old SDT_WebAssemblyCalls (NFC)
These are not used anymore.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94036
2021-01-04 16:31:16 -08:00
Kazu Hirata 0e219b6443 [Target] Construct SmallVector with iterator ranges (NFC) 2021-01-03 09:57:45 -08:00
Thomas Lively 5e09e9979b [WebAssembly] Prototype extending pairwise add instructions
As proposed in https://github.com/WebAssembly/simd/pull/380. This commit makes
the new instructions available only via clang builtins and LLVM intrinsics to
make their use opt-in while they are still being evaluated for inclusion in the
SIMD proposal.

Depends on D93771.

Differential Revision: https://reviews.llvm.org/D93775
2020-12-28 14:11:14 -08:00
Thomas Lively 44ee14f993 [WebAssembly][NFC] Finish cleaning up SIMD tablegen
This commit is a follow-on to c2c2e9119e73, using the `Vec` records introduced
in that commit in the rest of the SIMD instruction definitions. Also removes
unnecessary types in output patterns.

Differential Revision: https://reviews.llvm.org/D93771
2020-12-28 13:59:23 -08:00
Thomas Lively efe7f5ede0 [WebAssembly][NFC] Refactor SIMD load/store tablegen defs
Introduce `Vec` records, each bundling all information related to a single SIMD
lane interpretation. This lets TableGen definitions take a single Vec parameter
from which they can extract information rather than taking multiple redundant
parameters. This commit refactors all of the SIMD load and store instruction
definitions to use the new `Vec`s. Subsequent commits will similarly refactor
additional instruction definitions.

Differential Revision: https://reviews.llvm.org/D93660
2020-12-22 20:06:12 -08:00
Thomas Lively a781a706b9 [WebAssembly][SIMD] Rename shuffle, swizzle, and load_splats
These instructions previously used prefixes like v8x16 to signify that they were
agnostic between float and int interpretations. We renamed these instructions to
remove this form of prefix in https://github.com/WebAssembly/simd/issues/297 and
https://github.com/WebAssembly/simd/issues/316 and this commit brings the names
in LLVM up to date.

Differential Revision: https://reviews.llvm.org/D93722
2020-12-22 14:29:06 -08:00
Kazu Hirata 966f1431de [Target] Use llvm::erase_if (NFC) 2020-12-20 17:43:22 -08:00
Derek Schuff 8d396acac3 [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
This is a reland of rG4564553b8d8a with a fix to the lit pipeline in
llvm/test/MC/WebAssembly/comdat.ll
2020-12-10 16:43:59 -08:00
Derek Schuff dd1aa4fdd8 Revert "[WebAssembly] Support COMDAT sections in assembly syntax"
This reverts commit 4564553b8d.
It broke several buildbots.
2020-12-10 15:55:33 -08:00
Derek Schuff 4564553b8d [WebAssembly] Support COMDAT sections in assembly syntax
This CL changes the asm syntax for section flags, making them more like ELF
(previously "passive" was the only option). Now we also allow "G" to designate
COMDAT group sections. In these sections we set the appropriate comdat flag on
function symbols, and also avoid auto-creating a new section for them.

This also adds asm-based tests for the changes D92691 to go along with
the direct-to-object tests.

Differential Revision: https://reviews.llvm.org/D92952
2020-12-10 14:46:24 -08:00
Sam Clegg 1b6d879ec1 [WebAssembly] Fix code generated for atomic operations in PIC mode
The main this this test does is to add the `IsNotPIC` predicate to the
all the atomic instructions pattern that directly refer to
`tglobaladdr`.

This is because in PIC mode we need to generate separate instruction
sequence (either a direct global.get, or __memory_base + offset) for
accessing global addresses.

As part of this change I noticed that many of the `Requires` attributes
added to the instruction in `WebAssemblyInstrAtomics.td` were being
honored.  This is because the wrapped in a `let Predicates =
[HasAtomics]` block and it seems that that outer wrapping overrides any
`Requires` on defs within it.   As a workaround I removed the outer
`let` and added `HasAtomics` to all the inner `Requires`.  I believe
that all the instrucitons that don't have `Requires` explicit bottom out
in `ATOMIC_I` and `ATOMIC_NRI` which have `HasAtomics` so this should
not remove this predicate from any patterns (at least that is the idea).

The alternative to this approach looks like implementing something
like `PredicateControl` in `Mips.td` where we can split the predicates
into groups so they don't clobber each other.

Differential Revision: https://reviews.llvm.org/D92744
2020-12-08 18:41:32 -08:00
Heejin Ahn 60653e24b6 [WebAssembly] Support select and block for reference types
This adds missing `select` instruction support and block return type
support for reference types. Also refactors WebAssemblyInstrRef.td and
rearranges tests in reference-types.s. Tests don't include `exnref`
types, because we currently don't support `exnref` for `ref.null` and
the type will be removed soon anyway.

Reviewed By: tlively, sbc100, wingo

Differential Revision: https://reviews.llvm.org/D92359
2020-12-01 19:16:57 -08:00
snek 803af31e5b [WebAssembly] Support fp reg class in r constraint
Patch by snek

Reviewed By: aheejin

Differential Revision: https://reviews.llvm.org/D90978
2020-11-18 17:05:58 -08:00
Florian Hahn b2f4c5fddc
[AsmWriter] Factor out mnemonic generation to accessible getMnemonic.
This patch factors out the part of printInstruction that gets the
mnemonic string for a given MCInst. This is intended to be used
subsequently for the instruction-mix remarks to display the final
mnemonic (D90040).

Unfortunately making `getMnemonic` available to the AsmPrinter
seems to require making it virtual. Not sure if there's a way around
that with the current layering of the AsmPrinters.

Reviewed By: Paul-C-Anagnostopoulos

Differential Revision: https://reviews.llvm.org/D90039
2020-11-17 09:47:38 +00:00
Sam Clegg a083b28a31 [WebAssembly] Move GlobalTLSAddress handling to WebAssemblyISelLowering. NFC
I'm not why it was added to DAGToDAG oringally but it seems
to make sense alongside the non-TLS version:  LowerGlobalAddress

Differential Revision: https://reviews.llvm.org/D91432
2020-11-13 14:35:51 -08:00
Heejin Ahn 902ea588ea [WebAssembly] Rename atomic.notify and *.atomic.wait
- atomic.notify -> memory.atomic.notify
- i32.atomic.wait -> memory.atomic.wait32
- i64.atomic.wait -> memory.atomic.wait64

See https://github.com/WebAssembly/threads/pull/149.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D91447
2020-11-13 12:04:48 -08:00
Wouter van Oortmerssen 16f02431dc [WebAssembly] Added R_WASM_FUNCTION_OFFSET_I64 for use with DWARF DW_AT_low_pc
Needed for wasm64, see discussion in https://reviews.llvm.org/D91203

Differential Revision: https://reviews.llvm.org/D91395
2020-11-13 09:32:31 -08:00
Sam Clegg a28a466210 [WebAssembly] Add new relocation type for TLS data symbols
These relocations represent offsets from the __tls_base symbol.

Previously we were just using normal MEMORY_ADDR relocations and relying
on the linker to select a segment-offset rather and absolute value in
Symbol::getVirtualAddress().  Using an explicit relocation type allows
allow us to clearly distinguish absolute from relative relocations based
on the relocation information alone.

One place this is useful is being able to reject absolute relocation in
the PIC case, but still accept TLS relocations.

Differential Revision: https://reviews.llvm.org/D91276
2020-11-13 07:59:29 -08:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
No longer rely on an external tool to build the llvm component layout.

Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.

These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.

Differential Revision: https://reviews.llvm.org/D90848
2020-11-13 10:35:24 +01:00
Julien Jorge 0fca651711 [WebAssembly] Don't fold frame offset for global addresses
When machine instructions are in the form of
```
%0 = CONST_I32 @str
%1 = ADD_I32 %stack.0, %0
%2 = LOAD 0, 0, %1
```

In the `ADD_I32` instruction, it is possible to fold it if `%0` is a
`CONST_I32` from an immediate number. But in this case it is a global
address, so we shouldn't do that. But we haven't checked if the operand
of `ADD` is an immediate so far. This fixes the problem. (The case
applies the same for `ADD_I64` and `CONST_I64` instructions.)

Fixes https://bugs.llvm.org/show_bug.cgi?id=47944.

Patch by Julien Jorge (jjorge@quarkslab.com)

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D90577
2020-11-03 14:56:25 -08:00
Jordan Rupprecht 980bf1d5d1 [NFC] Inline wasm assertion-only variable 2020-11-03 13:06:59 -08:00
Andy Wingo 107c3a12d6 [WebAssembly] Implement ref.null
This patch adds a new "heap type" operand kind to the WebAssembly MC
layer, used by ref.null. Currently the possible values are "extern" and
"func"; when typed function references come, though, this operand may be
a type index.

Note that the "heap type" production is still known as "refedtype" in
the draft proposal; changing its name in the spec is
ongoing (https://github.com/WebAssembly/reference-types/issues/123).

The register form of ref.null is still untested.

Differential Revision: https://reviews.llvm.org/D90608
2020-11-03 10:46:23 -08:00
Thomas Lively a787e09779 [WebAssembly] Prototype i64x2.bitmask
As proposed in https://github.com/WebAssembly/simd/pull/368.

Differential Revision: https://reviews.llvm.org/D90514
2020-10-30 17:23:30 -07:00
Wouter van Oortmerssen 86cd2332ce [WebAssembly] Fixed DWARF DW_AT_low_pc encoded as 64-bit in wasm64
Also added general wasm64 DWARF test
Also added asserts for unsupported reloc combinations that triggered this bug.

Differential Revision: https://reviews.llvm.org/D90503
2020-10-30 16:42:48 -07:00
Thomas Lively 0a512a555a [WebAssembly] Prototype i64x2.eq
As proposed in https://github.com/WebAssembly/simd/pull/381. Since it is still
in the prototyping phase, it is only accessible via a target builtin function
and a target intrinsic.

Depends on D90504.

Differential Revision: https://reviews.llvm.org/D90508
2020-10-30 16:38:15 -07:00
Thomas Lively 1cb0b56607 [WebAssembly] Prototype i64x2.widen_{low,high}_i32x4_{s,u}
As proposed in https://github.com/WebAssembly/simd/pull/290. As usual, these
instructions are available only via builtin functions and intrinsics while they
are in the prototyping stage.

Differential Revision: https://reviews.llvm.org/D90504
2020-10-30 15:44:04 -07:00
Thomas Lively be6f50798e [WebAssembly] Implement SIMD signselect instructions
As proposed in https://github.com/WebAssembly/simd/pull/124, using the opcodes
adopted by V8 in
https://chromium-review.googlesource.com/c/v8/v8/+/2486235/2/src/wasm/wasm-opcodes.h.
Uses new builtin functions and a new target intrinsic exclusively to ensure that
the new instructions are only emitted when a user explicitly opts in to using
them since they are still in the prototyping and evaluation phase.

Differential Revision: https://reviews.llvm.org/D90357
2020-10-29 11:06:20 -07:00
Thomas Lively 31e944556f [WebAssembly] Prototype extending multiplication SIMD instructions
As proposed in https://github.com/WebAssembly/simd/pull/376. This commit
implements new builtin functions and intrinsics for these instructions, but does
not yet add them to wasm_simd128.h because they have not yet been merged to the
proposal. These are the first instructions with opcodes greater than 0xff, so
this commit updates the MC layer and disassembler to handle that correctly.

Differential Revision: https://reviews.llvm.org/D90253
2020-10-28 09:38:59 -07:00
Paulo Matos 69e2797eae [WebAssembly] Implementation of (most) table instructions
Implementation of instructions table.get, table.set, table.grow,
table.size, table.fill, table.copy.

Missing instructions are table.init and elem.drop as they deal with
element sections which are not yet implemented.

Added more tests to tables.s

Differential Revision: https://reviews.llvm.org/D89797
2020-10-23 08:42:54 -07:00
Thomas Lively 1992e30c2d [WebAssembly] Prototype i8x16.popcnt
As proposed at https://github.com/WebAssembly/simd/pull/379. Use a target
builtin and intrinsic rather than normal codegen patterns to make the
instruction opt-in until it is merged to the proposal and stabilized in engines.

Differential Revision: https://reviews.llvm.org/D89446
2020-10-15 21:18:22 +00:00
Thomas Lively 3f738d1f5e Reland "[WebAssembly] v128.load{8,16,32,64}_lane instructions"
This reverts commit 7c8385a352 with a typing fix
to an instruction selection pattern.
2020-10-15 19:32:34 +00:00
Thomas Lively 7c8385a352 Revert "[WebAssembly] v128.load{8,16,32,64}_lane instructions"
This reverts commit 7c6bfd90ab.
2020-10-15 15:49:36 +00:00
Thomas Lively 7c6bfd90ab [WebAssembly] v128.load{8,16,32,64}_lane instructions
Prototype the newly proposed load_lane instructions, as specified in
https://github.com/WebAssembly/simd/pull/350. Since these instructions are not
available to origin trial users on Chrome stable, make them opt-in by only
selecting them from intrinsics rather than normal ISel patterns. Since we only
need rough prototypes to measure performance right now, this commit does not
implement all the load and store patterns that would be necessary to make full
use of the offset immediate. However, the full suite of offset tests is included
to make it easy to track improvements in the future.

Since these are the first instructions to have a memarg immediate as well as an
additional immediate, the disassembler needed some additional hacks to be able
to parse them correctly. Making that code more principled is left as future
work.

Differential Revision: https://reviews.llvm.org/D89366
2020-10-15 15:33:10 +00:00
Paulo Matos 388fb67b0d [WebAssembly] Added .tabletype to asm and multiple table support in obj files
Adds more testing in basic-assembly.s and a new test tables.s.
Adds support to yaml reading and writing of tables as well.

Differential Revision: https://reviews.llvm.org/D88815
2020-10-13 07:52:23 -07:00
Thomas Lively 72c628e835 Reland "[WebAssembly] Emulate v128.const efficiently""
This reverts commit 432e4e56d3, which reverted 542523a61a. Two issues from
the original commit have been fixed. First, MSVC does not like when std::array
is initialized with only single braces, so this commit switches to using the
more portable double braces. Second, there was a subtle endianness bug that
prevented the original commit from working correctly on big-endian machines,
which has been fixed by switching to using endianness-agnostic bit twiddling
instead of type punning.

Differential Revision: https://reviews.llvm.org/D88773
2020-10-13 04:36:59 +00:00
Thomas Lively d8f58bf53a [WebAssembly] Prototype i16x8.q15mulr_sat_s
This saturating, rounding, Q-format multiplication instruction is proposed in
https://github.com/WebAssembly/simd/pull/365.

Differential Revision: https://reviews.llvm.org/D88968
2020-10-09 21:17:53 +00:00
Mircea Trofin 4cfc4025cc [NFC][MC] MCRegister API typing.
Mostly LiveIntervals, with their effects (users).

Differential Revision: https://reviews.llvm.org/D89018
2020-10-08 15:08:34 -07:00
Heejin Ahn 750b3ddd80 [WebAssembly] Handle indirect uses of longjmp
In LowerEmscriptenEHSjLj, `longjmp` used to be replaced with
`emscripten_longjmp_jmpbuf(jmp_buf*, i32)`, which will eventually be
lowered to `emscripten_longjmp(i32, i32)`. The reason we used two
different names was because they had different signatures in the IR
pass.

D88697 fixed this by only using `emscripten_longjmp(i32, i32)` and
adding a `ptrtoint` cast to its first argument, so
```
longjmp(buf, 0)
```
becomes
```
emscripten_longjmp((i32)buf, 0)
```

But this assumed all uses of `longjmp` was a direct call to it, which
was not the case. This patch handles indirect uses of `longjmp` by
replacing
```
longjmp
```
with
```
(i32(*)(jmp_buf*, i32))emscripten_longjmp
```

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D89032
2020-10-08 11:37:19 -07:00
Simon Pilgrim 0328005515 Fix MSVC "not all control paths return a value" warning. NFCI. 2020-10-07 19:53:39 +01:00
Heejin Ahn 3bba91f64e [WebAssembly] Rename Emscripten EH functions
Renaming for some Emscripten EH functions has so far been done in
wasm-emscripten-finalize tool in Binaryen. But recently we decided to
make a compilation/linking path that does not rely on
wasm-emscripten-finalize for modifications, so here we move that
functionality to LLVM.

Invoke wrappers are generated in LowerEmscriptenEHSjLj pass, but final
wasm types are not available in the IR pass, we need to rename them at
the end of the pipeline.

This patch also removes uses of `emscripten_longjmp_jmpbuf` in
LowerEmscriptenEHSjLj pass, replacing that with `emscripten_longjmp`.
`emscripten_longjmp_jmpbuf` is lowered to `emscripten_longjmp`, but
previously we generated calls to `emscripten_longjmp_jmpbuf` in
LowerEmscriptenEHSjLj pass because it takes `jmp_buf*` instead of `i32`.
But we were able use `ptrtoint` to make it use `emscripten_longjmp`
directly here.

Addresses:
https://github.com/WebAssembly/binaryen/issues/3043
https://github.com/WebAssembly/binaryen/issues/3081

Companions:
https://github.com/WebAssembly/binaryen/pull/3191
https://github.com/emscripten-core/emscripten/pull/12399

Reviewed By: dschuff, tlively, sbc100

Differential Revision: https://reviews.llvm.org/D88697
2020-10-07 09:42:49 -07:00
Stella Stamenova 432e4e56d3 Revert "[WebAssembly] Emulate v128.const efficiently"
This reverts commit 542523a61a.
2020-10-02 09:26:21 -07:00
Thomas Lively 542523a61a [WebAssembly] Emulate v128.const efficiently
v128.const was recently implemented in V8, but until it rolls into Chrome
stable, we can't enable it in the WebAssembly backend without breaking origin
trial users. So far we have been lowering build_vectors that would otherwise
have been lowered to v128.const to splats followed by sequences of replace_lane
instructions to initialize each lane individually. That produces large and
inefficient code, so this patch introduces new logic to lower integer vector
constants to a single i64x2.splat where possible, with at most a single
i64x2.replace_lane following it if necessary.

Adapted from a patch authored by @omnisip.

Differential Revision: https://reviews.llvm.org/D88591
2020-10-02 00:28:06 -07:00
Thomas Lively 89fe083c19 [WebAssembly] Check features before making SjLj vars thread-local
1c5a3c4d38 updated the variables inserted by Emscripten SjLj lowering to be
thread-local, depending on the CoalesceFeaturesAndStripAtomics pass to downgrade
them to normal globals if the target features did not support TLS. However, this
had the unintended side effect of preventing all non-TLS-supporting objects from
being linked into modules with shared memory, because stripping TLS marks an
object as thread-unsafe. This patch fixes the problem by only making the SjLj
lowering variables thread-local if the target machine supports TLS so that it
never introduces new usage of TLS that will be stripped. Since SjLj lowering
works on Modules instead of Functions, this required that the
WebAssemblyTargetMachine have its feature string updated to reflect the
coalesced features collected from all the functions so that a
WebAssemblySubtarget can be created without using any particular function.

Differential Revision: https://reviews.llvm.org/D88323
2020-09-25 11:45:16 -07:00
Thomas Lively 1c5a3c4d38 [WebAssembly] Make SjLj lowering globals thread-local
Emscripten's longjump and exception mechanism depends on two global variables,
`__THREW__` and `__threwValue`, which are changed to be defined as thread-local
in https://github.com/emscripten-core/emscripten/pull/12056. This patch updates
the corresponding code in the WebAssembly backend to properly declare these
globals as thread-local as well.

Differential Revision: https://reviews.llvm.org/D88262
2020-09-24 14:56:19 -07:00
Mircea Trofin 6e85c3d5c7 [NFC][Regalloc] accessors for 'reg' and 'weight'
Also renamed the fields to follow style guidelines.

Accessors help with readability - weight mutation, in particular,
is easier to follow this way.

Differential Revision: https://reviews.llvm.org/D87725
2020-09-16 08:28:57 -07:00
Craig Topper c193a689b4 [SelectionDAG] Use Align/MaybeAlign in calls to getLoad/getStore/getExtLoad/getTruncStore.
The versions that take 'unsigned' will be removed in the future.

I tried to use getOriginalAlign instead of getAlign in some
places. getAlign factors in the minimum alignment implied by
the offset in the pointer info. Since we're also passing the
pointer info we can use the original alignment.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D87592
2020-09-14 13:54:50 -07:00
Sam Clegg fa2a8acc71 [WebAssembly] Add assembly syntax for mutable globals
This adds and optional ", immutable" to the end of a `.globaltype`
declaration.  I would have prefered to match the `.wat` syntax
where immutable is the default and `mut` is the signifier for
mutable globals.  Sadly changing the default would break backwards
compat with existing assembly in the wild so I think its best
to stick with this approach.

Differential Revision: https://reviews.llvm.org/D87515
2020-09-11 11:11:02 -07:00
Dominic Chen 4252f3009b
[WebAssembly] Set unreachable as canonical to permit disassembly
Currently, using llvm-objdump to disassemble a function containing
unreachable will trigger an assertion while decoding the opcode, since both
unreachable and debug_unreachable have the same encoding. To avoid this, set
unreachable as the canonical decoding.

Differential Revision: https://reviews.llvm.org/D87431
2020-09-10 15:04:16 -04:00
Heejin Ahn d25c17f317 [WebAssembly] Fix fixEndsAtEndOfFunction for try-catch
When the function return type is non-void and `end` instructions are at
the very end of a function, CFGStackify's `fixEndsAtEndOfFunction`
function fixes the corresponding block/loop/try's type to match the
function's return type. This is applied to consecutive `end` markers at
the end of a function. For example, when the function return type is
`i32`,
```
block i32    ;; return type is fixed to i32
  ...
  loop i32   ;; return type is fixed to i32
    ...
  end_loop
end_block
end_function
```

But try-catch is a little different, because it consists of two parts:
a try part and a catch part, and both parts' return type should satisfy
the function's return type. Which means,
```
try i32      ;; return type is fixed to i32
  ...
  block i32  ;; this should be changed i32 too!
    ...
  end_block
catch
  ...
end_try
end_function
```
As you can see in this example, it is not sufficient to only `end`
instructions at the end of a function; in case of `try`, we should
check instructions before `catch`es, in case their corresponding `try`'s
type has been fixed.

This changes `fixEndsAtEndOfFunction`'s algorithm to use a worklist
that contains a reverse iterator, each of which is a starting point for
a new backward `end` instruction search.

Fixes https://bugs.llvm.org/show_bug.cgi?id=47413.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D87207
2020-09-08 09:27:40 -07:00
Thomas Lively caee15a0ed [WebAssembly] Fix incorrect assumption of simple value types
Fixes PR47375, in which an assertion was triggering because
WebAssemblyTargetLowering::isVectorLoadExtDesirable was improperly
assuming the use of simple value types.

Differential Revision: https://reviews.llvm.org/D87110
2020-09-06 15:42:21 -07:00
Simon Pilgrim 83ca548fcb WebAssemblyUtilities.h - reduce unnecessary includes to forward declarations. NFCI. 2020-09-03 17:43:35 +01:00
Craig Topper aab90384a3 [Attributes] Add a method to check if an Attribute has AttrKind None. Use instead of hasAttribute(Attribute::None)
There's a special case in hasAttribute for None when pImpl is null. If pImpl is not null we dispatch to pImpl->hasAttribute which will always return false for Attribute::None.

So if we just want to check for None its sufficient to just check that pImpl is null. Which can even be done inline.

This patch adds a helper for that case which I hope will speed up our getSubtargetImpl implementations.

Differential Revision: https://reviews.llvm.org/D86744
2020-08-28 13:23:45 -07:00
Craig Topper c7a0b2684f [X86][MC][Target] Initial backend support a tune CPU to support -mtune
This patch implements initial backend support for a -mtune CPU controlled by a "tune-cpu" function attribute. If the attribute is not present X86 will use the resolved CPU from target-cpu attribute or command line.

This patch adds MC layer support a tune CPU. Each CPU now has two sets of features stored in their GenSubtargetInfo.inc tables . These features lists are passed separately to the Processor and ProcessorModel classes in tablegen. The tune list defaults to an empty list to avoid changes to non-X86. This annoyingly increases the size of static tables on all target as we now store 24 more bytes per CPU. I haven't quantified the overall impact, but I can if we're concerned.

One new test is added to X86 to show a few tuning features with mismatched tune-cpu and target-cpu/target-feature attributes to demonstrate independent control. Another new test is added to demonstrate that the scheduler model follows the tune CPU.

I have not added a -mtune to llc/opt or MC layer command line yet. With no attributes we'll just use the -mcpu for both. MC layer tools will always follow the normal CPU for tuning.

Differential Revision: https://reviews.llvm.org/D85165
2020-08-14 15:31:50 -07:00
Thomas Lively d53d952810 [WebAssembly] Allow inlining functions with different features
Allow inlining only when the Callee has a subset of the Caller's
features. In principle, we should be able to inline regardless of any
features because WebAssembly supports features at module granularity,
not function granularity, but without this restriction it would be
possible for a module to "forget" about features if all the functions
that used them were inlined.

Requested in PR46812.

Differential Revision: https://reviews.llvm.org/D85494
2020-08-13 13:57:43 -07:00
Jordan Rupprecht 1a67522d3e [NFC] Inline variable only used in debug builds 2020-08-11 19:38:01 -07:00
Thomas Lively 2985c02f79 [WebAssembly][AsmParser] Name missing features in error message
Rather than just saying that some feature is missing, report the exact
features to make the error message more useful and actionable.

Differential Revision: https://reviews.llvm.org/D85795
2020-08-11 17:26:14 -07:00
Thomas Lively 1a69f02397 [WebAssembly][NFC] Replace WASM with standard Wasm
The officially specified abbreviation for WebAssembly is Wasm and the
spec explicitly calls out WASM as being an incorrect spelling. This
patch fixes a few comments and error messages to use the
spec-compliant abbreviation.

Differential Revision: https://reviews.llvm.org/D85764
2020-08-11 12:27:59 -07:00
Wouter van Oortmerssen 582fd474dd [WebAssembly] wasm64: fix memory.init operand types
I had assumed they would all become in i64, but this is not necessary as long as data segments stay 32-bit, see:
https://github.com/WebAssembly/memory64/blob/master/proposals/memory64/Overview.md

Differential Revision: https://reviews.llvm.org/D85552
2020-08-10 10:15:20 -07:00
Thomas Lively cc612c2908 [WebAssembly] Fix FastISel address calculation bug
Fixes PR47040, in which an assertion was improperly triggered during
FastISel's address computation. The issue was that an `Address` set to
be relative to the FrameIndex with offset zero was incorrectly
considered to have an unset base. When the left hand side of an add
set the Address to be 0 off the FrameIndex, the right side would not
detect that the Address base had already been set and could try to set
the Address to be relative to a register instead, triggering an
assertion.

This patch fixes the issue by explicitly tracking whether an `Address`
has been set rather than interpreting an offset of zero to mean the
`Address` has not been set.

Differential Revision: https://reviews.llvm.org/D85581
2020-08-08 15:23:11 -07:00
Thomas Lively cb32792210 [WebAssembly] Implement prototype v128.load{32,64}_zero instructions
Specified in https://github.com/WebAssembly/simd/pull/237, these
instructions load the first vector lane from memory and zero the other
lanes. Since these instructions are not officially part of the SIMD
proposal, they are only available on an opt-in basis via LLVM
intrinsics and clang builtin functions. If these instructions are
merged to the proposal, this implementation will change so that the
instructions will be generated from normal IR. At that point the
intrinsics and builtin functions would be removed.

This PR also changes the opcodes for the experimental f32x4.qfm{a,s}
instructions because their opcodes conflicted with those of the
v128.load{32,64}_zero instructions. The new opcodes were chosen to
match those used in V8.

Differential Revision: https://reviews.llvm.org/D84820
2020-08-03 13:54:00 -07:00
Fangrui Song 40da58a04b [MC] Default MCAsmBackend::mayNeedRelaxation() to false 2020-08-02 22:13:59 -07:00
Wouter van Oortmerssen ce1eb7af9d [WebAssembly] Fixed 64-bit indices in br_table
LLVM selection dag assumes "switch" indices are pointer sized, which causes problems for our 32-bit br_table. The new function ensures 32-bit operands don't get unnecessarily extended, and 64-bit operands get truncated.

Note that the changes to the existing test test exactly that: the addition of -NEXT in 2 places ensures no extension is inserted (which the test previously ignored) and that the wrap is present (previously omitted in wasm64 mode).

Differential Revision: https://reviews.llvm.org/D84705
2020-07-30 10:52:16 -07:00
Craig Topper 3632f765dc [WebAssembly] Fix GCC 5 build.
Hans' speculative fix in b7292f2db0
didn't work for me. This seems to.
2020-07-30 10:00:28 -07:00
Hans Wennborg b7292f2db0 Speculative GCC 5 build fix
It's complaining about specializing the template in a different namespace.
2020-07-30 16:12:52 +02:00
Heejin Ahn 276f9e8cfa [WebAssembly] Fix getBottom for loops
When it was first created, CFGSort only made sure BBs in each
`MachineLoop` are sorted together. After we added exception support,
CFGSort now also sorts BBs in each `WebAssemblyException`, which
represents a `catch` block, together, and
`Region` class was introduced to be a thin wrapper for both
`MachineLoop` and `WebAssemblyException`.

But how we compute those loops and exceptions is different.
`MachineLoopInfo` is constructed using the standard loop computation
algorithm in LLVM; the definition of loop is "a set of BBs that are
dominated by a loop header and have a path back to the loop header". So
even if some BBs are semantically contained by a loop in the original
program, or in other words dominated by a loop header, if they don't
have a path back to the loop header, they are not considered a part of
the loop. For example, if a BB is dominated by a loop header but
contains `call abort()` or `rethrow`, it wouldn't have a path back to
the header, so it is not included in the loop.

But `WebAssemblyException` is wasm-specific data structure, and its
algorithm is simple: a `WebAssemblyException` consists of an EH pad and
all BBs dominated by the EH pad. So this scenario is possible: (This is
also the situation in the newly added test in cfg-stackify-eh.ll)

```
Loop L: header, A, ehpad, latch
Exception E: ehpad, latch, B
```
(B contains `abort()`, so it does not have a path back to the loop
header, so it is not included in L.)

And it is sorted in this order:
```
header
A
ehpad
latch
B
```

And when CFGStackify places `end_loop` or `end_try` markers, it
previously used `WebAssembly::getBottom()`, which returns the latest BB
in the sorted order, and placed the marker there. So in this case the
marker placements will be like this:
```
loop
  header
  try
    A
  catch
    ehpad
    latch
end_loop         <-- misplaced!
    B
  end_try
```
in which nesting between the loop and the exception is not correct.
`end_loop` marker has to be placed after `B`, and also after `end_try`.

Maybe the fundamental way to solve this problem is to come up with our
own algorithm for computing loop region too, in which we include all BBs
dominated by a loop header in a loop. But this takes a lot more effort.
The only thing we need to fix is actually, `getBottom()`. If we make it
return the right BB, which means in case of a loop, the latest BB of the
loop itself and all exceptions contained in there, we are good.

This renames `Region` and `RegionInfo` to `SortRegion` and
`SortRegionInfo` and extracts them into their own file. And add
`getBottom` to `SortRegionInfo` class, from which it can access
`WebAssemblyExceptionInfo`, so that it can compute a correct bottom
block for loops.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D84724
2020-07-29 10:36:32 -07:00
Thomas Lively 11bb7eef41 [WebAssembly] Remove intrinsics for SIMD widening ops
Instead, pattern match extends of extract_subvectors to generate
widening operations. Since extract_subvector is not a legal node, this
is implemented via a custom combine that recognizes extract_subvector
nodes before they are legalized. The combine produces custom ISD nodes
that are later pattern matched directly, just like the intrinsic was.

Also removes the clang builtins for these operations since the
instructions can now be generated from portable code sequences.

Differential Revision: https://reviews.llvm.org/D84556
2020-07-28 18:25:55 -07:00